Inam

i Lab

orat

ory

/ Th

e U

niv

ersi

ty o

f E

lect

ro-C

omm

un

icat

ion

sSmart Light –Ultra High Speed Projector for Spatial Multiplexing Optical Transmission

Hideaki NII, Maki SUGIMOTO, Masahiko INAMI

The University of Erectro-Communications, JAPAN

Inam

i Lab

orat

ory

/ Th

e U

niv

ersi

ty o

f E

lect

ro-C

omm

un

icat

ion

s

Table of contents

• Introduction– Camera vs. Projector– Comparison of characteristics

• Smart light concept (next to projector)

• Preliminary experiment• The design of LED projector• Experiment of LED projector• Conclusion

Inam

i Lab

orat

ory

/ Th

e U

niv

ersi

ty o

f E

lect

ro-C

omm

un

icat

ion

s

Projector vs. video camera

• Acquire images.• Acquire

information with images

• Project images• Project

information with images.

Camera Projector

A projector is the dual of a camera. R Raskar, iLamps,2003

Inam

i Lab

orat

ory

/ Th

e U

niv

ersi

ty o

f E

lect

ro-C

omm

un

icat

ion

s

Basic concept of image-processing

Camera (1)we send position data by LED,(2)acquire images by video camera, (3)processing and recoginize a position, (4) get (X,Y) position data.

deviceCCD

(X,Y)LED× 1

Inam

i Lab

orat

ory

/ Th

e U

niv

ersi

ty o

f E

lect

ro-C

omm

un

icat

ion

s

Basic concept of projector image processing

Projector(1) we project color images depending on its x-cordinate or Y-cordinate position, (2) a device acquire color values by color sensor,(3) get (X,Y) position data.

deviceprojector

Inam

i Lab

orat

ory

/ Th

e U

niv

ersi

ty o

f E

lect

ro-C

omm

un

icat

ion

s

Projector-Based Tracking SystemDemonstrated at SIGGRAPH2004

Inam

i Lab

orat

ory

/ Th

e U

niv

ersi

ty o

f E

lect

ro-C

omm

un

icat

ion

s

Augmented ColiseumTo be Demonstrated at

SIGGRAPH2005

Inam

i Lab

orat

ory

/ Th

e U

niv

ersi

ty o

f E

lect

ro-C

omm

un

icat

ion

s

A compact battery-less information terminal (CoBIT) for location-based support systems

Takuichi Nishimura, SPIE, number 4863B-12, 2002

CoBIT can project various kinds of information according to a position. But LED light can project only single sound.

Inam

i Lab

orat

ory

/ Th

e U

niv

ersi

ty o

f E

lect

ro-C

omm

un

icat

ion

s

RFIG Lamp

• Use RFID and a portable projector to display RFID tag’s location directly.

http://www.merl.com/people/raskar/Sig04/

Inam

i Lab

orat

ory

/ Th

e U

niv

ersi

ty o

f E

lect

ro-C

omm

un

icat

ion

s

Smart light concept

• Use projector and camera to communicate to detached device.

• To increase band-width, use space division .

Make invisibleinfomation

make vision

Computer

Capture image from camera

High speed camera

Devices

Projector

+

Half mirror

Control module

Inam

i Lab

orat

ory

/ Th

e U

niv

ersi

ty o

f E

lect

ro-C

omm

un

icat

ion

s

Why LED projector ?

Most high-speed pixel :LED

Class Frame rate

LCD projector 60[Hz]

DMD projector

10,000[Hz]

LED projector 10,000,000[Hz]

Inam

i Lab

orat

ory

/ Th

e U

niv

ersi

ty o

f E

lect

ro-C

omm

un

icat

ion

s

Preliminary experiment

Photo detectorPICReceiveLED

Projector

averageregister

Pulse widthto digital

+

-comp

wave formstabilizer

sensorinput

Detectoutput PIC internal

function

Image A

Image B

20HzOSCImage A Image B

AMP

Luminance of A and B (cd/m2)

Response from detector

Response from subject

82;82 No No

82;88 Yes Yes

82;95 Yes Yes

77;77 No No

77;72 Yes No

77;67 Yes Yes

Result

Detector

Experimental setup

Inam

i Lab

orat

ory

/ Th

e U

niv

ersi

ty o

f E

lect

ro-C

omm

un

icat

ion

s

Experiment of LED projector

A B

B

A

0 28.8

30.4

30.5 65.0

O nly A

A and B

O nly B

[m m]

7.2m

m

L E D -BL E N S S C R E E N

L E D -AC irc le o f B

C irc le o f A

Result

Positional relationship

LE D

Camera

Lens

S creen

Photosensor

FM modulation

FM modulation FM demodulation

Headphone

Experimental setup

To check the signal separation quality. We prepare this experimental set.

50mm 300mm

Inam

i Lab

orat

ory

/ Th

e U

niv

ersi

ty o

f E

lect

ro-C

omm

un

icat

ion

s

LED projector

• Can project small image for human’s eye

• Can project invisible information (sound/video stream) .

• Different data stream to each pixel.

• Projection pattern can change in real time.

• Subject can select the point by the detector and get data stream with no time delay.

Inam

i Lab

orat

ory

/ Th

e U

niv

ersi

ty o

f E

lect

ro-C

omm

un

icat

ion

s

Components of LED projector

InputA

InputB

InputC

InputD

Selector

AMP

AMP

AMP

AMP

AMP

Select Input-signal from communication I/FRS232C

Selector

Selector

Selector

OSC

OSC

OSC

OSC

LED1

LED2

LED3

LED4

LED20

6mm 8.5mm

6mm

7.5m

m

40mm

29mm

Inam

i Lab

orat

ory

/ Th

e U

niv

ersi

ty o

f E

lect

ro-C

omm

un

icat

ion

s

Experiment of LED projector

lens

detector1

detector2

spatial light modulator

time-spatial modulation light

detector3

Inam

i Lab

orat

ory

/ Th

e U

niv

ersi

ty o

f E

lect

ro-C

omm

un

icat

ion

s

Experiment of LED projector

LED projector and signal generator Photo detector and headset

Portable musicplayer(MUSIC)

Portable musicplayer(NOISE)

FM modulation

FM modulation

LED Prjector

Pixel luminance and input sound controller

FM de-modulation

Photo detector

Headphone

Inam

i Lab

orat

ory

/ Th

e U

niv

ersi

ty o

f E

lect

ro-C

omm

un

icat

ion

s

Characteristic of this experiment

• Subject can see bright area and dark area on the screen.

• The bright area has music stream for the headphone, and the dark area has noise.

• Subject can select the point by the detector and hear a sound stream with no time delay.

• The bright area has move in rhythm of the music.

• As the result, subject can move a detector in rhythm of music and listen a music continuously.

Inam

i Lab

orat

ory

/ Th

e U

niv

ersi

ty o

f E

lect

ro-C

omm

un

icat

ion

s

Inam

i Lab

orat

ory

/ Th

e U

niv

ersi

ty o

f E

lect

ro-C

omm

un

icat

ion

s

Conclusion

• Concept of “Smart light”.• Fundamental experiment of LED

projector.• Design of LED projector.• The experiment of LED projector.

Inam

i Lab

orat

ory

/ Th

e U

niv

ersi

ty o

f E

lect

ro-C

omm

un

icat

ion

s

Thank you